The Steam Packet's sailings on Saturday and Sunday are at risk of the disruption because of forecast adverse weather.
Nearly all the weekend's crossings to and from Heysham could be cancelled because of strong winds.
The 2.15am sailing from Heysham on Saturday morning is expected to leave to schedule, but the weekend's eight other sailings could be disrupted by conditions in the Irish Sea.
This includes the 1.20pm sailing from the Lancashire port to Douglas in the early hours of Monday morning.